accretion disk

noun

variants or less commonly accretion disc

plural accretion disks also accretion discs

: a disk of usually gaseous matter surrounding a massive celestial object (such as a black hole) in which the matter gradually spirals in toward and accretes onto the object as a result of gravitational attraction

Evans' team studied a supermassive black hole with jets 800 million light-years away named 3C 33. They never found an expected X-ray pattern … which results from light reflecting off the accretion disk.

—Bill Andrews

Most other moons are either captured planetesimals, or they formed along with the planet in a common accretion disc.

—Daniel Herwartz, et al.

Examples of accretion disk in a Sentence

Recent Examples on the Web

Interacting material, like normal matter, forms accretion disks surrounding massive objects. —Big Think, 4 May 2026

The immense gravity of the black hole heats the accretion disk, causing the powerful X-ray emissions associated with Cyg X-1. —Robert Lea, Space.com, 21 Apr. 2026

Some of the stellar guts failed to escape and fell back toward the newborn magnetar, forming a small accretion disk around it. —Jacek Krywko, ArsTechnica, 13 Mar. 2026

This debris field in the disk is almost certainly asymmetrical, meaning the spin axis of both the accretion disk and magnetar are misaligned. —Andrew Paul, Popular Science, 11 Mar. 2026

Word History

First Known Use

1972, in the meaning defined above

Rhymes for accretion disk

• videodisc
• basilisk
• obelisk
• bisque
• brisk
• disc
• fisc
• fisk
• frisk
• risk
• whisk